Add PHPStan static analysis

composer.json

@@ -34,10 +34,13 @@
 		"mockery/mockery": "^1.6",
 		"php-parallel-lint/php-parallel-lint": "^1.4",
 		"phpcompatibility/phpcompatibility-wp": "^2",
+		"phpstan/extension-installer": "^1.4",
+		"phpstan/phpstan": "^2.2",
 		"phpunit/phpunit": "^9.6",
 		"rector/rector": "^2.4",
 		"roave/security-advisories": "dev-latest",
 		"squizlabs/php_codesniffer": "^3",
+		"szepeviktor/phpstan-wordpress": "^2.0",
 		"wp-coding-standards/wpcs": "^3",
 		"yoast/phpunit-polyfills": "^4"
 	},
@@ -58,7 +61,8 @@
 			"composer/installers": true,
 			"dealerdirect/phpcodesniffer-composer-installer": true,
 			"ergebnis/composer-normalize": true,
-			"infection/extension-installer": true
+			"infection/extension-installer": true,
+			"phpstan/extension-installer": true
 		},
 		"sort-packages": true
 	},
@@ -72,6 +76,7 @@
 			"@php ./vendor/bin/parallel-lint . --exclude vendor --exclude node_modules",
 			"bin/xml-lint"
 		],
+		"phpstan": "phpstan analyse",
 		"rector": "@php ./vendor/bin/rector process --dry-run",
 		"rector:fix": "@php ./vendor/bin/rector process",
 		"test": [
@@ -100,6 +105,7 @@
 		"infection": "Run mutation testing with Infection.",
 		"integration": "Deprecated alias for test:integration, kept until CI moves to the new script names.",
 		"lint": "Check PHP files for syntax errors and XML config files against their schemas.",
+		"phpstan": "Run static analysis with PHPStan.",
 		"rector": "Preview automated refactorings with Rector (dry run).",
 		"rector:fix": "Apply automated refactorings with Rector.",
 		"test": "Run the quick checks: lint, coding standards, and unit tests.",

phpstan.neon.dist

@@ -0,0 +1,18 @@
+# PHPStan configuration.
+#
+# The WordPress stubs and rules are loaded automatically from
+# szepeviktor/phpstan-wordpress via phpstan/extension-installer.
+#
+# views/ and config/ are deliberately not analysed: those files are pulled in
+# via include/require and rely on variables injected into their scope at
+# runtime (template data, plugin constants), which PHPStan cannot see.
+#
+# Level 8 is the ceiling for this codebase: level 9 adds checkExplicitMixed,
+# which fights the untyped boundary of config-driven WordPress code — the
+# BrightNucleus Config accessors return mixed by design. Revisit if the
+# config ever gains a typed accessor layer.
+parameters:
+	level: 8
+	paths:
+		- plugin-slug.php
+		- src